Lululemon Athletica Inc. appears to still be facing one of the highest quality problems in retail: demand running ahead of supply.

Credit Suisse analyst Christian Buss has been tracking product availability both in-store and online, as well as monitoring the level of online discounting every week since June.

He found that only 67% of Lululemon’s products are available online at any given time, producing a sell-out rate of 33% that is high relative to the company’s peers.

Checks with staff at 14 stores highlight similar challenges keeping product in stock, while discounting remains modest with an average of 9% of online product on sale and an average discount of 30%.

Mr. Buss noted that Lululemon’s inventory build-up was aggressive in the first quarter, rising 67% year-over-year on second quarter sales growth guidance of 30%. However, the company exited the first quarter with just 75 days of forward inventory, which remains at the low end of the specialty retail landscape.

This leaves the analyst quite comfortable with his above-guidance estimates for comparable same-store sales, revenue and EPS of 14%, US$285.4-million and US32¢, respectively.